CODEWITHSUNDEEP
javascriptjsonmultidimensional-array
Jasmin
Jasmin

Reputation: 39

How to access specific value from a nested array within an object array?

I am trying to get a specific field value from a nested array within an object array. I'm assuming I'd use map, but every time I use it in this way I get two empty arrays nested inside two empty objects. I know this is wrong, I'm just showing where my thinking process is going.

function getChildArray(item, index) {
   var x = [item.hobbies]
      return x
}

console.log(parentArray.map(getChildArray))

This is an example of my document structure:

[  
   {  
      "id":12345678900,
      "name":"Jasmin",
      "age":27,
      "hobbies":[  
         {  
            "id":1221,
            "name":"hiking",
            "when":"anytime"
         },
         {  
            "id":9865,
            "name":"eating",
            "when":"all the time"
         }
      ]
   },
   {  
      "id":223456789001,
      "name":"Joe",
      "age":35,
      "hobbies":[  
         {  
            "id":989,
            "name":"gaming",
            "when":"anytime"
         },
         {  
            "id":2355,
            "name":"online gaming",
            "when":"all the time"
         }
      ]
   }
]

How would I, for example, be able to retrieve a list of Joe's hobbies by name only?

Upvotes: 0

Views: 654

Answers (3)

KevBot
KevBot

Reputation: 18908

Since array.find is not available in all browsers yet, and you may not be using a build tool, here is a complete ES5 way. It uses filter and map:

var data = [{ id: 12345678900, name: 'Jasmin', age: 27, hobbies: [{'id': 1221, 'name': 'hiking', 'when': 'anytime'}, { 'id': 9865, 'name': 'eating', 'when': 'all the time' }] }, { id: 223456789001, name: 'Joe', age: 35, hobbies: [{'id': 989, 'name':
'gaming', 'when': 'anytime'}, { 'id': 2355, 'name': 'online gaming', 'when': 'all the time' }]}];


function getHobbiesByName(name) {
  return data.filter(function(person) {
    return (person.name == name);
  })[0].hobbies.map(function(hobby) {
    return hobby.name
  })
}

console.log(getHobbiesByName('Joe'))

Upvotes: 1

ElDoRado1239
ElDoRado1239

Reputation: 4048

A quick function to return an item with the desired property and value of that property :

data = [{id:1,name:'Bob',hobbies:['a','b']},{id:2,name:'Alice',hobbies:['c','d']}];

function getPerson(property,value){
 for(var i=0;i<data.length;i++) if(data[i][property] == value) return data[i];
 return {};
}

And a test :

console.log(getPerson('name','Bob'));
console.log(getPerson('name','Bob').hobbies);

Upvotes: 0

Marco Scabbiolo
Marco Scabbiolo

Reputation: 7469

var joe = parentArray.find(function (item) {
    return item.name === 'Joe';
});

if (joe) {
    var joesHobbiesNames = joe.hobbies.map(function (hobbie) {
       return hobbie.name;
    });
}

Or in ES6

var joe = parentArray.find((item) => item.name === 'Joe');

if (joe) {
    var joesHobbiesNames = joe.hobbies.map((hobbie) => hobbie.name);
}

Upvotes: 2

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